Brake Porportioning Vave

[Stewy49]

I'm going to try and use a booster/master cylinder set up out of a trailblazer with disc/disc and wanted to see if I can get some opinions on what proportioning valve would be good to use with this set up? Thanks!

[Daze57]

if i were you i would try to get the p-valve that is attached to the MC . or at least if your yardin the MC take the p-valve with it

if not get the year of the blazer and buy a new p valve - may not be a bad idea to take a pict of old one just to match up ,
hope that helps

[_Ogre]

i use an 03 mustang cobra mc, i used the pvalve attached to it. works well.
i'd do like daze suggests and try the one on the mc you get
i bought an add on pvalve never installed it, that was 4 yrs ago

[Stewy49]

I thought the p-valve that they used with this had some sort of abs in with it. If it does can it still be used and just leave any wires for the abs unhooked? Thanks!

[Daze57]

i think you can do that but i am not 100% sure. i hope others chime in to help you out

[_Ogre]

Abs is after the p valve. Will have 2 lines from mc in, 4 out to each wheel.
It will be a fairly big box. The p valve might have 2 wires for the differential spool.
It will shift and give a warning if you have a problem, tripping a switch

[mknittle]

When I did the hydroboost on my jeep I used a willwood adjustable proportioning valve in the rear line after the balance valve(P valve) To stop the rear wheels from locking before the fronts.

[Stewy49]

Here are some pics, if they load. Of the box that the lines from the master cylinder went to. It looks like 2 lines went in and 3 out, And if 2 lines went to the front and 1 to the back and split. Not sure what the round black thing and the gray box attached to it are. Any ideas if this thing might still work? Thanks.

[_Ogre]

that is not a proportional valve
that is the antilock brakes box, i wouldn't use that
edit... unless you want antilock brakes and have complete knowledge of what it takes to hook it up and make it work

[Stewy49]

That makes sense, I thought it had to much stuff on it to be a proportioning valve. Maybe it's all in one unit, as this was the first thing the lines from the master cylinder went to. I figured it would be useless, I'll just have to by a universal one. Thanks for info.

[Jyman]

I don't think a disc/disc set up has a p-valve, because they should push all the wheels at the same amount. unlike the disc/drum set up would need the p-valve. but I could be wrong on this one

[_Ogre]

you want more braking on the rear of a vehicle, especially when you hit the brakes and unload the back of a vehicle. this would cause the rear brakes to lock up and put the vehicle in a spin if you were cornering. all modern vehicles use a proportional valve.

stewy, if your interested i have a new adjustable prop valve in my for parts sale section of this forum
i bought it to install it on my truk, but the oem mustang pvalve balanced my brakes fine.

[Stewy49]

Thanks Ogre, I might be interested in it. So I would just use this on my rears and run the fronts straight from the m/c to the calipers?

[_Ogre]

yes, an adjustable proportioning valve is all you need. insert the proportioning valve into the rear brake line. basically the set procedure is to go 45 mph down the road, apply the brakes hard, if your rear brakes lock before the front brakes, adjust the flow down. repeat this procedure until you get balanced braking.